Meeting Report: Harnessing Volcanic and Geothermal Resources for Sustainable Development in the East African Rift Open Report OR/18/065

Meeting report: Harnessing Volcanic and Geothermal Resources for Sustainable Development in the East African Rift Open Report OR/18/065

BRITISH GEOLOGICAL SURVEY

OPEN REPORT OR/18/065

Meeting report: Harnessing Volcanic and Geothermal Resources for Sustainable Development in the Keywords Volcanic; geothermal; resources, East African Rift; workshop; East African Rift Kenya.

Front cover A gorge exposing layered pumice C.A. Rochelle deposits at the Hells Gate National Park next to the Olkaria Geothermal Field. Note the volcanic plug at the top of the image, which was fed by the glassy feeder dyke in the centre of the image.

Bibliographical reference C.A. ROCHELLE. 2018. Meeting report: Harnessing Volcanic and geothermal Resources for Sustainable Development in the East African Rift. British Geological Survey Open Report, OR/18/065. 22pp. Copyright in materials derived from the British Geological Survey’s work is owned by UK Research and Innovation (UKRI) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, e-mail [email protected]. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract.

BRITISH GEOLOGICAL SURVEY The full range of our publications is available from BGS shops at British Geological Survey offices Nottingham, Edinburgh, London and Cardiff (Welsh publications only) see contact details below or shop online at Environmental Science Centre, Keyworth, Nottingham www.geologyshop.com NG12 5GG The London Information Office also maintains a reference Tel 0115 936 3100 collection of BGS publications, including maps, for consultation. BGS Central Enquiries Desk We publish an annual catalogue of our maps and other publications; this catalogue is available online or from any of the Tel 0115 936 3143 BGS shops. email [email protected]

The British Geological Survey carries out the geological survey of BGS Sales Great Britain and Northern Ireland (the latter as an agency service for the government of Northern Ireland), and of the Tel 0115 936 3241 surrounding continental shelf, as well as basic research projects. email [email protected] It also undertakes programmes of technical aid in geology in developing countries. The Lyell Centre, Research Avenue South, Edinburgh EH14 4AP The British Geological Survey is a component body of UK Tel 0131 667 1000 Research and Innovation. email [email protected]

Natural History Museum, Cromwell Road, London SW7 5BD Tel 020 7589 4090 Tel 020 7942 5344/45 email [email protected]

Cardiff University, Main Building, Park Place, Cardiff CF10 3AT Tel 029 2167 4280

Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB Tel 01491 838800

Geological Survey of Northern Ireland, Department of Enterprise, Trade & Investment, Dundonald House, Upper Newtownards Road, Ballymiscaw, Belfast, BT4 3SB Tel 01232 666595 www.bgs.ac.uk/gsni/

Natural Environment Research Council, Polaris House, North Star Avenue, Swindon SN2 1EU Tel 01793 411500 Fax 01793 411501 www.nerc.ac.uk

UK Research and Innovation, Polaris House, Swindon SN2 1FL Tel 01793 444000 www.ukri.org

Website www.bgs.ac.uk Shop online at www.geologyshop.com

Foreword

This report is the published product of the British Geological Survey (BGS) and summarises key observations from a workshop held at Niavasha, Kenya, 17-20 September 2018. Its primary purpose was as a ‘getting to know you’ workshop focused on sharing knowledge about volcanoes and geothermal in the East African Rift. This was made possible because of a £25k Global Challenges Research Fund grant awarded Prof David Pyle of Oxford University, who linked with Prof Nicholas Marita of Dedan Kimathi University of Technology, Nairobi. This allowed 6 UK participants to travel to Kenya for the meeting, and approximately three times that number to attend from a range of countries along the East African Rift.

Acknowledgements

The Global Challenges Research Fund is gratefully acknowledged for providing funding to allow this workshop to happen. Especially thanked are Dr Karen Fontijn (University of Oxford, UK, now Université Libre de Bruxelles, Belgium), Prof David Pyle (University of Oxford, UK) and Prof Nicholas Marita (Dedan Kimathi University of Technology, Kenya) for their work in arranging and running the meeting. The workshop was funded by a Global Challenges Research Fund Networking Grant from the Academy of Medical Sciences, grant number GCRFNG100310, 1/2/2018 – 31/1/2019. The BGS work research was also supported by BGS NC-ODA grant NE/R000069/1 entitled ‘Geoscience for Sustainable Futures’. It was delivered via the BGS Eastern Africa Official Development Assistance (ODA) Research Platform.

Contents

Foreword ...... i

Acknowledgements ...... i

Contents ...... ii

1 Introduction and Background ...... 1

2 Attendees and Science Areas ...... 1

3 Agenda ...... 1 3.1 Overview of East African Rift Geology ...... 1 3.2 Scientific Presentations...... 2 3.3 Field Visits ...... 3

4 Key observations from the meeting ...... 5

Appendix 1 ...... 16

Appendix 2 ...... 21

FIGURES

Figure 1. On a rift escarpment viewpoint looking out over the East African Rift...... 8 Figure 2. Some of the workshop participants...... 8 Figure 3. A typical breakout group discussion...... 9 Figure 4. At the entrance of the Menengai Geothermal Field...... 9 Figure 5. A large rig drilling a new borehole at the Menengai Geothermal Field. White containers on the right hand side give a sense of scale...... 10 Figure 6. A typical production well at the Menengai Geothermal Field...... 10 Figure 7. Greenhouse close to one of the wells at Menengai, where geothermal water is used to provide heat at night for the growing of capsicums (and previously, tomatoes) ...... 11 Figure 8. Small ponds used to demonstrate the use of geothermal heat to help rear tilapia...... 11 Figure 9. Examining diffuse areas of gas venting at the Menengai Geothermal Field...... 12 Figure 10. Overview of pipework at power production facilities at the Olkaria Geothermal Field...... 12 Figure 11. Entrance to the geothermal spa at the Olkaria Geothermal Field...... 13 Figure 12. Turquoise geothermal waters in the outside pool at the Olkaria Geothermal Field. .. 13 Figure 13. Demonstrating fluid sampling from a pipeline at the Olkaria Geothermal Field...... 14 Figure 14. Walking through a gorge exposing layered pumice deposits at the Hells Gate National Park next to the Olkaria Geothermal Field...... 14 Figure 15. A gorge exposing layered pumice deposits at the Hells Gate National Park next to the Olkaria Geothermal Field. Note the volcanic plug at the top of the image, which was fed by the glassy feeder dyke in the centre of the image...... 15

iii

1 Introduction and Background

The East African Rift (EAR) passes through a range of countries and encompasses a range of resources such as geothermal systems, mineralisation and gases. As the region is tectonically active, it also hosts potential hazards, such as active volcanoes. Achieving a better understanding of resource potential is central to furthering the long-term stability and development of these countries. With this in mind, Prof David Pyle of Oxford University submitted a proposal to the Global Challenges Research Fund (GCRF) so that a workshop could be held to bring together leading African and UK scientists with an interest in the sustainable development of volcanic and geothermal resources. This was in conjunction with Prof Nicholas Marita of Dedan Kimathi University of Technology, Nairobi. A £25k grant was awarded to Prof Pyle, and a workshop was organised at Burch’s Resort, Niavasha, Kenya on the 17-20 September 2018. This was entitled ‘Harnessing Volcanic and Geothermal resources for Sustainable Development In The East African Rift’. This report describes a summary of that meeting. The primary purposes of the workshop were to share experience and knowledge of the EAR, and for UK and African researchers to get to know each other better (many had never met before). This was to be achieved through lectures, practical demonstrations, and field visits (see agenda in Appendix 1). The overall aim of the meeting was to help create new opportunities, project ideas and long-term partnerships.

2 Attendees and Science Areas

Six researchers travelled from the UK (4 from Oxford University, 1 from Glasgow University, and 1 from the BGS), and 16 came from Africa from a mixture of Kenya, Ethiopia, Tanzania, Djibuti and the DRC (plus others from Kenya at various times). A full listing of attendees is given in Appendix 2. Key senior Kenyan academics who were present were: - Prof Nicholas Marita of Dedan Kimathi University of Technology, Nairobi. - Prof Daniel Ichang’i of the University of Nairobi. Though the initial concept was for an equal emphasis on volcanoes and geothermal systems, the meeting turned out to be heavily skewed towards high temperature geothermal systems. The interest from the Oxford University participants was mainly volcanic. Whilst risk was not talked about too much (mainly as the volcanoes interest group was smaller than expected), it was noted that >25M people in Kenya live within 30 km of EAR volcanoes.

3 Agenda

3.1 OVERVIEW OF EAST AFRICAN RIFT GEOLOGY The first day (described in the agenda as Day 0) was a travel day from Nairobi. However, during the journey we stopped at an escarpment viewpoint and looked out over the East African Rift (Figure 1). Discussion about general rift geology and mechanisms of formation. The Eastern Rift is more active (more magma emplacement, larger magma chambers and compositional differentiation), whereas the Western Rift is more passive (mainly crustal stretching with fewer volcanoes).

Specific discussion about the volcanic geology of Mount Suswa and Mount Longonot. Bimodal distribution of volcanoes and magma composition. Lots of fissure-type eruptions of more basic lava, but where sizable magma chambers build up (under larger volcanoes) differentiation can take place, and more silicic magma is produced (plenty of evidence of obsidian at the surface). There are also high alkali content magmas which produce low viscosity lavas. The first evening mainly involved an ‘icebreaker’ session, and this was followed up with short participant introductions the following morning (Figure 2).

3.2 SCIENTIFIC PRESENTATIONS Day 1 was consisted of sessions of related talks, each of which was about 15 minutes long. General overview of EAR geology and volcano-related resources: • Introduction of EAR geology • Introduction to EAR volcanology and volcanic hazards • Introduction to EAR geothermal systems • Introduction to gas monitoring • Introduction to mineral resources Geothermal companies: • Geothermal development Company (GDC) • KenGen (Olkaria) • Geothermal Development in Djibouti Active research projects: • Volcanic and seismic monitoring in the Western Branch of the EAR • Update on geothermal exploration/exploitation and direct-use applications in the Kenyan Rift • RiftVolc – past, present and future volcanism in the Main Ethiopian Rift • Helium resources in young rift basins surrounding the Tanzanian Craton • Gas surveys to identify structures at Menengai

Day 2 took more of a forward look towards opportunities. Future research developments: • Training of earth sciences in Africa • UK / Africa / other funding sources • Industry perspective and collaboration with academia Breakout groups (Figure 4): • What are the main research priorities for the next 10 years? • What are the primary challenges and needs for geoscience in Africa? • How can international collaborations be improved? Introduction to field visits: • Menengai • Olkaria Demonstration of gas sampling techniques: • Oxford University and noble gas methods. • Glasgow University and soil gas methods. • BGS and soil gas and noble gas methods.

3.3 FIELD VISITS These visits were arranged to give us an overview of geothermal operations, and included information on general geology, surveying, drilling, production, powerplant, and environmental monitoring.

3.3.1 Menengai Day 3 was a visit to the Menengai geothermal site. This geothermal field lies within a well-defined, approximately 10 km diameter, caldera (Figure 4). This is being developed by the Geothermal Development Company1 (GDC). The field is in a stage of active development, with over 40 wells drilled feeding an installed capacity of >165 MWe, and currently has 7 large drill rigs on the site (3 were actively drilling at the time of our visit, Figures 5 and 6). Production is only moderate, suggesting either a lower permeability reservoir formation of limited fracturing.

We visited: • Malima Punda (the highest point within the caldera) for an overview of caldera geology). Last eruption about 200 years ago. • Direct use of geothermal energy (well MW-03, Figure 5), with small-scale tests ongoing in greenhouses (Figure 7), fish tanks (Figure 8), launderette, and milk pasteurisation. • Well pad visit to an actively drilling well ([MW-15?] very noisy, were shown round the drilling operations, talked to the site geologist [had long conversation regarding samples and mineralogy]). • Fumarole visit and demonstration of gas sampling (Figure 9). • Visit to well pad number 1, with wells under test. • Road cutting at the edge of the caldera showing a good exposure of pyroclastic deposits.

Items of note from this visit: - Drilled into molten rock three times at about 2.2 km. No blowouts or pressure problems, just the drills getting stuck as the molten rock sets around them. - No warning signs of being about to hit magma, which suggests it is relatively young as it has not altered the surrounding rock (last eruption there was about 200 years ago). They have a reasonable idea where the boundary of the suspected ‘dome-like’ magma chamber is, so the drillers stop the wells just 100-200m above the magma chamber. - There is a clear parallel in terms of scientific interests and opportunities with the Krafla Magma Testbed (KMT). Lots of potential science could be done in terms of magma processes and studies of the glass. Given that there are 7 big rigs on site, one wonders if the ‘KMT concept’ might actually be more workable at Menengai (the ‘MMT’?). - I did not see samples of the recovered glass, but understand more about the situation there having spoken to the site geologist (who has looked at the glass in thin section). - Helen Robinson (Glasgow PhD student) has been doing soil gas and resistivity surveys in the area. Whilst this gas survey is constrained by the vegetation in the area, there is scope for both wider area coverage to identify changes towards the edge of the caldera, and also closer-spaced sampling for higher resolution studies.

1 http://www.gdc.co.ke 3

3.3.2 Olkaria Day 4 was a visit to the Olkaria geothermal site. The Olkaria geothermal field also lies within a ring structure, but it is less well defined than the caldera at Menengai – it is not just a simple caldera. This is run by KenGen2. This is a very large and well-developed field, and is the site of the first geothermal powerplant in Kenya (Figure 10). It is split into 8 or so individual production areas, each of which is as large as some other geothermal fields. There are 281 wells over the site, with an installed capacity of capacity >660 MWe. The reservoir has very good permeability over large areas, and production rates rare high. We visited: • The Olkaria geothermal spa (Figures 11 and 12) • The KenGen geoscience labs • Olkaria II viewpoint • Demonstration of geochemical sampling (water and gas) (Figure 13) • Tour of the Ololbutot crater • Olkaria I power station • A geothermal well under active fluid production and discharge • Short tour of the Ol Njorowa Gorge and the Hells Gate National Park (volcanic features, hot springs, lots of animals, Figures 14 1nd 15).

Items of note from this visit: - Olkaria was Africa’s first geothermal plant, and is now a huge complex of about 8 different geothermal prospects. - KenGen have a very fancy new office at the entrance to the site – looks very much like a ‘statement building’. KenGen are working on building a geothermal centre of excellence on adjacent land for geothermal training. - I saw some of their water and gas monitoring techniques demonstrated. Sampling of produced fluids from the wellhead looked sensible, producing a range of waters and gas samples for analysis. Field gas monitoring techniques were more basic however, and appears somewhat laborious. The BGS methods appear far more efficient, and may deliver a wider range of gas measurements. - Gas monitoring/surveying to identify the surface expressions of open faults/fractures would be useful, as would fracture mapping. - Time-series gas monitoring at fixed sites would also be useful to get information on the impact of production over time (e.g. semi-permanent autonomous stations etc, as per what BGS has deployed elsewhere). - 3D modelling of the site. KenGen have a 3D model of major conductive fractures, but this structural model appears to be quite simple. GIS treatment and focussed new data acquisition would seem to be an opportunity for the BGS.

2 http://www.kengen.co.ke 4

4 Key observations from the meeting

The following observations are not in a particular order, though some key points are underlined to highlight them: • The workshop was a very good opportunity to meet a wide range of African geoscientists from several countries. In particular, it was excellent in terms of meeting Kenyan geoscientists, and good contacts were made with the two key Kenyan geothermal companies, KenGen and GDC. • KenGen have about 69% of Kenyan electric supply and are nationally owned. They cover everything from site exploration, drilling and power production. GDC are private, and are only allowed to explore and develop sites, selling steam to independent power producers. The relationship between the 2 companies (and with the universities) seemed quite complex. Whilst these companies employed graduates from Kenyan universities, there was clearly a barrier in terms of academic researchers accessing equipment held by the companies. • The science areas covered during the workshop were broad ranging, but included: lots of gas monitoring, fluid chemistry, geological structures, metal deposit formation, but only some geophysics. • BGS got several mentions in terms of its historical work in the area and the preliminary geothermal investigations of the 1970s and 80s. The Kenyans were complimentary about the past BGS work, and it appeared that the BGS data underpinned the decisions to exploit the geothermal systems. We should be able to build upon this positive view. Some of the Kenyans only had poor photocopies of the reports. Note: There is an easy win in terms of collating good quality digital copies of all the BGS reports from that era and making them available. • There are several clear areas where we can work with the Kenyans, and these should be investigated further. Possibilities include: - Big area surveys of the rift or transects across the rift (e.g. remote sensing, seismics, gas and water monitoring) aimed at (more of an academic) understanding rift processes and possibly also resource evaluation. It seemed to me that there were only limited datasets at this scale, and that wider-scale surveys could highlight areas of interest for more detailed investigation. - Surveys focused on specific sites (e.g. high-resolution gas monitoring, thermal imaging) to investigate volcanic or geothermal processes (the former of more academic interest, the latter linked with geothermal exploitation). Also potential for surveys linked to oil/gas, helium, and metals. NOTE: Whilst some satellite-based work and INSAR have been done, it is noteworthy that Kenya has just (spring 2018) legalized the use of UAVs – so detailed UAV-based imaging/monitoring of sites may be something BGS could undertake. Also, there are only 4 or 5 permanent seismic stations in the country, and they can’t detect low intensity events, so developing this infrastructure is an opportunity. • Menengai: The GDC have drilled into molten rock three times at about 2.2 km. The igneous body appears to be ‘dome-shaped’. Lots of potential science could be done in terms of magma processes and studies of the glass samples recovered. NOTE: There is potential for cutting edge science here, with clear links to similar BGS interests in Iceland and the KMT. There is a specific potential opportunity for the BGS in terms of high resolution microanalysis and spectroscopic studies. As ideas of what to investigate already exist, this could be geared up relatively quickly. • Menengai: Some surface gas monitoring data exist, but this is limited in extent.

NOTE: There are opportunities to extend this gas monitoring in terms of area covered, gases analysed and degree of spatial resolution. • Olkaria: This was Africa’s first geothermal plant, and is now a huge complex of about 8 different geothermal prospects. I saw some of their gas monitoring work, it is quite basic – we could do far more, and far more quickly. NOTE: There are opportunities for gas monitoring, but this time at a site-scale (or one geothermal prospect at a time). Time-series gas monitoring at fixed sites could also be useful to identify any temporal changes as a result of steam production. • Olkaria: 3D modelling of the site. KenGen have a 3D model of major conductive fractures, but this structural model appears to be relatively simple (at least from what I saw in their presentation). NOTE: There could be opportunities to develop this model further, though a first step would be to conduct a detailed initial assessment of current model. There may be potential for GIS treatment and focussed new data acquisition, which could be an opportunity for the BGS. • Both Menengai and Olkaria: Many samples of drill chips (and possibly a few cores) are being taken at regular intervals, but it was not clear than anything other than basic optical microscopy was being done on the samples. NOTE: There appears much scope for higher resolution studies (such as by SEM), and mineral geothermometry (± fluid inclusions), which are the types of geothermal investigations that the BGS has done in the past. • It is clear that the academics from the African countries represented at the workshop had very little access to equipment (and in the case of the DRC, even access to field areas on safety grounds). They were keen to utilize the laboratory facilities run by KenGen and the GDC lab - though those companies appeared more reticent to do this. NOTE: There is clear potential for any future joint UK-Africa projects to have a component of African students utilizing equipment in the UK (even if most of their work is based in Africa). However, we should be careful to ensure that skills learned can be sustainably transferred to the local situations in Africa (i.e. not accentuate the current ‘brain drain’ of African researchers because they don’t have local access to equipment that they have been trained to use). • There seems to have been a gap in training geologists in Kenya from about the 1990s – so there is a bit of a skills shortage within mid-career scientists. • The Rift Valley has held lakes of large size during the geologic past, allowing the build-up of organic-rich sediments. Locally high geothermal gradients have facilitated breakdown of these organics and the liberation of gas and heavier hydrocarbons. Evidence for hydrocarbons is starting to be found in Kenya, which they are keen to exploit if there are sufficient deposits. NOTE: Gas monitoring is a clear potential future area of work – both large areal coverage at low resolution, and higher resolution coverage at site-scale. • There is evidence for other types of gas resources. Unusually high concentrations of helium have been found in vents near the Tanzania craton3 (>10% helium, with the remainder being nitrogen). A company has been formed to explore for helium resources (it is hoped that a reservoir of free gas will exist at depth). In terms of CO2 resources, there is at least one borehole (in Kenya, at the very edge of the rift escarpment) producing commercial quantities of CO2. Given the ubiquitous nature of this gas in rift settings, it is very likely that other such accumulations occur.

3 https://www.nation.co.ke/news/africa/Helium-worth-billions-found-in-Tanzania/1066- 3272268-ipj0d8/index.html 6

NOTE: Again, gas monitoring surveys appear a possible future area of work – both large areal coverage at low resolution, and higher resolution coverage at site scale. Helium could present specific analytical challenges in terms of analysis in the field, and consideration should be given to investing in specific mobile equipment to analyse for it. • In more southern parts of the EAR, there is increasing interest in exploiting the methane in deep waters in Lake Kivu. This is already being done to some extent in Rwanda, but the DRC would like to do this as well. NOTE: There is potential for limnology studies and gas monitoring, plus risk assessments.

Figure 1. On a rift escarpment viewpoint looking out over the East African Rift.

Figure 2. Some of the workshop participants.

Figure 3. A typical breakout group discussion (reproduced with permission of D. Pyle).

Figure 4. At the entrance of the Menengai Geothermal Field.

Figure 5. A large rig drilling a new borehole at the Menengai Geothermal Field. White containers on the right hand side give a sense of scale.

Figure 6. A typical production well at the Menengai Geothermal Field.

Figure 7. Greenhouse close to one of the wells at Menengai, where geothermal water is used to provide heat at night for the growing of capsicums (and previously, tomatoes).

Figure 8. Small ponds used to demonstrate the use of geothermal heat to help rear tilapia.

Figure 9. Examining diffuse areas of gas venting at the Menengai Geothermal Field.

Figure 10. Overview of pipework at power production facilities at the Olkaria Geothermal Field.

Figure 11. Entrance to the geothermal spa at the Olkaria Geothermal Field.

Figure 12. Turquoise geothermal waters in the outside pool at the Olkaria Geothermal Field.

Figure 13. Demonstrating fluid sampling from a pipeline at the Olkaria Geothermal Field.

Figure 14. Walking through a gorge exposing layered pumice deposits at the Hells Gate National Park next to the Olkaria Geothermal Field.

Figure 15. A gorge exposing layered pumice deposits at the Hells Gate National Park next to the Olkaria Geothermal Field. Note the volcanic plug at the top of the image, which was fed by the glassy feeder dyke in the centre of the image.

Appendix 1

Agenda distributed at the workshop (with annotations).

Agenda continued.

Appendix 2

List of participants.

List of participants continued.